Clone-specific expression, transcriptional regulation, and action of interleukin-6 in human colon carcinoma cells
Clone-specific expression, transcriptional regulation, and action of interleukin-6 in human colon carcinoma cells
复制标题
DOI：
10.1186/1471-2407-8-13
复制
发表时间：
2008-01-18
期刊：
影响因子：
3.8
通讯作者：
Peterlik, Meinrad
中科院分区：
文献类型：
--
作者：
Brozek, Wolfgang;Bises, Giovanna;Peterlik, Meinrad
背景资料：许多癌细胞产生白细胞介素-6（IL-6），这是一种在多种恶性肿瘤（包括结肠直肠癌）中的继发性肿瘤的生长刺激、转移和血管生成中起作用的细胞因子。IL-6在这方面的有效性可能取决于随着肿瘤进展通过恶性肿瘤阶段表达的基础和诱导型IL-6的量。因此，我们评估了IL-6调节剂的作用，即。e. IL-1 β，前列腺素E2，17 β-雌二醇，和1，25-二羟维生素D-3，在肿瘤进展的不同阶段的细胞因子的表达和合成，方法：我们利用培养的人结肠癌细胞克隆Caco-2/AQ，COGA-1A和COGA-13，所有这些都表示分化和增殖标志物的肿瘤进展的不同阶段的典型。采用RT-PCR和ELISA法分别检测IL-6 mRNA和蛋白水平。结果：高、中分化的Caco-2/AQ和COGA-1A细胞中IL-6 mRNA和蛋白表达水平较低，而低分化的COGA-13细胞中IL-6 mRNA和蛋白表达水平较高。向COGA-13培养物中添加IL-1 β（5 ng/ml）可通过非依那普利依赖性机制使IL-6产生增加约1000倍。添加17 β-雌二醇（10（-7）M）可使基础IL-6产生减少三分之一，但IL-1 β诱导型IL-6不受影响。对IL-6启动子多态性的研究揭示了一个单倍型的存在，即：例如，-597A/-572G/-174C，这与IL-6基因的高度转录活性有关。IL-6仅在Caco-2/AQ细胞中阻断分化，并通过上调c-myc原癌基因表达刺激有丝分裂。10（-8）M 1，25-dihydroxyvitamin D-3可抑制IL-6的这种作用。结论：在来源于高分化和中等分化肿瘤的人结肠癌细胞中，IL-6的表达较低，且仅受PGE（2）、1，25-dihydroxyvitamin D-3和17 β-雌二醇的轻微影响。然而，IL-6在未分化的肿瘤细胞中高度丰富，并且被IL-1 β有效地刺激。在对IL-1 β极端敏感的IL-6基因变体过表达的情况下，未分化的肿瘤细胞大量释放细胞因子可能通过对具有仍起作用的增殖性IL-6信号传导途径的更分化的肿瘤细胞的旁分泌作用而加速恶性进展。
Background: Many cancer cells produce interleukin-6 (IL-6), a cytokine that plays a role in growth stimulation, metastasis, and angiogenesis of secondary tumours in a variety of malignancies, including colorectal cancer. Effectiveness of IL-6 in this respect may depend on the quantity of basal and inducible IL-6 expressed as the tumour progresses through stages of malignancy. We therefore have evaluated the effect of IL-6 modulators, i. e. IL-1 beta, prostaglandin E2, 17 beta-estradiol, and 1,25-dihydroxyvitamin D-3, on expression and synthesis of the cytokine at different stages of tumour progression.Methods: We utilized cultures of the human colon carcinoma cell clones Caco-2/AQ, COGA-1A and COGA-13, all of which expressed differentiation and proliferation markers typical of distinct stages of tumour progression. IL-6 mRNA and protein levels were assayed by RT-PCR and ELISA, respectively. DNA sequencing was utilized to detect polymorphisms in the IL-6 gene promoter.Results: IL-6 mRNA and protein concentrations were low in well and moderately differentiated Caco-2/AQ and COGA-1A cells, but were high in poorly differentiated COGA-13 cells. Addition of IL-1 beta (5 ng/ml) to a COGA-13 culture raised IL-6 production approximately thousandfold via a prostaglandin-independent mechanism. Addition of 17 beta-estradiol (10(-7) M) reduced basal IL-6 production by one-third, but IL-1 beta-inducible IL-6 was unaffected. Search for polymorphisms in the IL-6 promoter revealed the presence of a single haplotype, i. e., -597A/-572G/-174C, in COGA-13 cells, which is associated with a high degree of transcriptional activity of the IL-6 gene. IL-6 blocked differentiation only in Caco-2/AQ cells and stimulated mitosis through up-regulation of c-myc proto-oncogene expression. These effects were inhibited by 10(-8) M 1,25-dihydroxyvitamin D-3.Conclusion: In human colon carcinoma cells derived from well and moderately differentiated tumours, IL-6 expression is low and only marginally affected, if at all, by PGE(2), 1,25-dihydroxyvitamin D-3, and 17 beta-estradiol. However, IL-6 is highly abundant in undifferentiated tumour cells and is effectively stimulated by IL-1 beta. In case of overexpression of an IL-6 gene variant with extreme sensitivity to IL-1 beta, massive release of the cytokine from undifferentiated tumour cells may accelerate progression towards malignancy by paracrine action on more differentiated tumour cells with a still functioning proliferative IL-6 signalling pathway.